8318324: Drop redundant default methods from FFM API

Reviewed-by: jvernee

src/java.base/share/classes/java/lang/foreign/MemoryLayout.java

@@ -26,14 +26,9 @@
 package java.lang.foreign;
 
 import java.lang.invoke.MethodHandle;
-import java.lang.invoke.MethodHandles;
-import java.lang.invoke.MethodType;
 import java.lang.invoke.VarHandle;
-import java.util.EnumSet;
 import java.util.Objects;
 import java.util.Optional;
-import java.util.Set;
-import java.util.function.Function;
 import java.util.stream.Stream;
 
 import jdk.internal.foreign.LayoutPath;
@@ -44,7 +39,6 @@ import jdk.internal.foreign.layout.PaddingLayoutImpl;
 import jdk.internal.foreign.layout.SequenceLayoutImpl;
 import jdk.internal.foreign.layout.StructLayoutImpl;
 import jdk.internal.foreign.layout.UnionLayoutImpl;
-import jdk.internal.vm.annotation.ForceInline;
 
 /**
  * A memory layout describes the contents of a memory segment.
@@ -404,35 +398,12 @@ public sealed interface MemoryLayout permits SequenceLayout, GroupLayout, Paddin
      * @throws IllegalArgumentException if {@code offset} or {@code index} is negative
      * @throws ArithmeticException if either the addition or multiplication overflows
      */
-    @ForceInline
+    long scale(long offset, long index);
-    default long scale(long offset, long index) {
-        if (offset < 0) {
-            throw new IllegalArgumentException("Negative offset: " + offset);
-        }
-        if (index < 0) {
-            throw new IllegalArgumentException("Negative index: " + index);
-        }
-
-        return Math.addExact(offset, Math.multiplyExact(byteSize(), index));
-    }
 
     /**
      *{@return a method handle that can be used to invoke {@link #scale(long, long)} on this layout}
      */
-    default MethodHandle scaleHandle() {
+    MethodHandle scaleHandle();
-        class Holder {
-            static final MethodHandle MH_SCALE;
-            static {
-                try {
-                    MH_SCALE = MethodHandles.lookup().findVirtual(MemoryLayout.class, "scale",
-                            MethodType.methodType(long.class, long.class, long.class));
-                } catch (ReflectiveOperationException e) {
-                    throw new ExceptionInInitializerError(e);
-                }
-            }
-        }
-        return Holder.MH_SCALE.bindTo(this);
-    }
 
     /**
      * Computes the offset, in bytes, of the layout selected by the given layout path, where the initial layout in the
@@ -444,10 +415,7 @@ public sealed interface MemoryLayout permits SequenceLayout, GroupLayout, Paddin
      * @throws IllegalArgumentException if the layout path contains one or more <a href=#open-path-elements>open path elements</a>.
      * @throws IllegalArgumentException if the layout path contains one or more <a href=#deref-path-elements>dereference path elements</a>.
      */
-    default long byteOffset(PathElement... elements) {
+    long byteOffset(PathElement... elements);
-        return computePathOp(LayoutPath.rootPath(this), LayoutPath::offset,
-                EnumSet.of(PathKind.SEQUENCE_ELEMENT, PathKind.SEQUENCE_RANGE, PathKind.DEREF_ELEMENT), elements);
-    }
 
     /**
      * Creates a method handle that computes the offset, in bytes, of the layout selected
@@ -482,10 +450,7 @@ public sealed interface MemoryLayout permits SequenceLayout, GroupLayout, Paddin
      * @throws IllegalArgumentException if the layout path is not <a href="#well-formedness">well-formed</a> for this layout.
      * @throws IllegalArgumentException if the layout path contains one or more <a href=#deref-path-elements>dereference path elements</a>.
      */
-    default MethodHandle byteOffsetHandle(PathElement... elements) {
+    MethodHandle byteOffsetHandle(PathElement... elements);
-        return computePathOp(LayoutPath.rootPath(this), LayoutPath::offsetHandle,
-                EnumSet.of(PathKind.DEREF_ELEMENT), elements);
-    }
 
     /**
      * Creates a var handle that accesses a memory segment at the offset selected by the given layout path,
@@ -577,14 +542,7 @@ public sealed interface MemoryLayout permits SequenceLayout, GroupLayout, Paddin
      * @throws IllegalArgumentException if the layout path is not <a href="#well-formedness">well-formed</a> for this layout.
      * @throws IllegalArgumentException if the layout selected by the provided path is not a {@linkplain ValueLayout value layout}.
      */
-    default VarHandle varHandle(PathElement... elements) {
+    VarHandle varHandle(PathElement... elements);
-        Objects.requireNonNull(elements);
-        if (this instanceof ValueLayout vl && elements.length == 0) {
-            return vl.varHandle(); // fast path
-        }
-        return computePathOp(LayoutPath.rootPath(this), LayoutPath::dereferenceHandle,
-                Set.of(), elements);
-    }
 
     /**
      * Creates a method handle which, given a memory segment, returns a {@linkplain MemorySegment#asSlice(long,long) slice}
@@ -623,10 +581,7 @@ public sealed interface MemoryLayout permits SequenceLayout, GroupLayout, Paddin
      * @throws IllegalArgumentException if the layout path is not <a href="#well-formedness">well-formed</a> for this layout.
      * @throws IllegalArgumentException if the layout path contains one or more <a href=#deref-path-elements>dereference path elements</a>.
      */
-    default MethodHandle sliceHandle(PathElement... elements) {
+    MethodHandle sliceHandle(PathElement... elements);
-        return computePathOp(LayoutPath.rootPath(this), LayoutPath::sliceHandle,
-                Set.of(PathKind.DEREF_ELEMENT), elements);
-    }
 
     /**
      * Returns the layout selected from the provided path, where the initial layout in the path is this layout.
@@ -638,23 +593,7 @@ public sealed interface MemoryLayout permits SequenceLayout, GroupLayout, Paddin
      * @throws IllegalArgumentException if the layout path contains one or more path elements that select one or more
      * sequence element indices, such as {@link PathElement#sequenceElement(long)} and {@link PathElement#sequenceElement(long, long)}).
      */
-    default MemoryLayout select(PathElement... elements) {
+    MemoryLayout select(PathElement... elements);
-        return computePathOp(LayoutPath.rootPath(this), LayoutPath::layout,
-                EnumSet.of(PathKind.SEQUENCE_ELEMENT_INDEX, PathKind.SEQUENCE_RANGE, PathKind.DEREF_ELEMENT), elements);
-    }
-
-    private static <Z> Z computePathOp(LayoutPath path, Function<LayoutPath, Z> finalizer,
-                                       Set<PathKind> badKinds, PathElement... elements) {
-        Objects.requireNonNull(elements);
-        for (PathElement e : elements) {
-            LayoutPath.PathElementImpl pathElem = (LayoutPath.PathElementImpl)Objects.requireNonNull(e);
-            if (badKinds.contains(pathElem.kind())) {
-                throw new IllegalArgumentException(String.format("Invalid %s selection in layout path", pathElem.kind().description()));
-            }
-            path = pathElem.apply(path);
-        }
-        return finalizer.apply(path);
-    }
 
     /**
      * An element in a <a href="MemoryLayout.html#layout-paths"><em>layout path</em></a>. There

src/java.base/share/classes/java/lang/foreign/MemorySegment.java

@@ -573,10 +573,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * the alignment constraint specified by {@code layout}.
      * @return a slice of this memory segment.
      */
-    default MemorySegment asSlice(long offset, MemoryLayout layout) {
+    MemorySegment asSlice(long offset, MemoryLayout layout);
-        Objects.requireNonNull(layout);
-        return asSlice(offset, layout.byteSize(), layout.byteAlignment());
-    }
 
     /**
      * Returns a slice of this memory segment, at the given offset. The returned segment's address is the address
@@ -788,10 +785,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      * @return this segment.
      */
-    default MemorySegment copyFrom(MemorySegment src) {
+    MemorySegment copyFrom(MemorySegment src);
-        MemorySegment.copy(src, 0, this, 0, src.byteSize());
-        return this;
-    }
 
     /**
      * Finds and returns the offset, in bytes, of the first mismatch between
@@ -820,10 +814,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws WrongThreadException if this method is called from a thread {@code T},
      * such that {@code other.isAccessibleBy(T) == false}.
      */
-    default long mismatch(MemorySegment other) {
+    long mismatch(MemorySegment other);
-        Objects.requireNonNull(other);
-        return MemorySegment.mismatch(this, 0, byteSize(), other, 0, other.byteSize());
-    }
 
     /**
      * Determines whether the contents of this mapped segment is resident in physical
@@ -1068,9 +1059,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws WrongThreadException if this method is called from a thread {@code T},
      * such that {@code isAccessibleBy(T) == false}.
      */
-    default String getString(long offset) {
+    String getString(long offset);
-        return getString(offset, sun.nio.cs.UTF_8.INSTANCE);
-    }
 
     /**
      * Reads a null-terminated string from this segment at the given offset, using the provided charset.
@@ -1099,10 +1088,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      *                                  such that {@code isAccessibleBy(T) == false}.
      * @throws IllegalArgumentException if {@code charset} is not a {@linkplain StandardCharsets standard charset}.
      */
-    default String getString(long offset, Charset charset) {
+    String getString(long offset, Charset charset);
-        Objects.requireNonNull(charset);
-        return StringSupport.read(this, offset, charset);
-    }
 
     /**
      * Writes the given string into this segment at the given offset, converting it to a null-terminated byte sequence
@@ -1123,10 +1109,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws WrongThreadException if this method is called from a thread {@code T},
      * such that {@code isAccessibleBy(T) == false}.
      */
-    default void setString(long offset, String str) {
+    void setString(long offset, String str);
-        Objects.requireNonNull(str);
-        setString(offset, str, sun.nio.cs.UTF_8.INSTANCE);
-    }
 
     /**
      * Writes the given string into this segment at the given offset, converting it to a null-terminated byte sequence
@@ -1160,11 +1143,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      *                                  such that {@code isAccessibleBy(T) == false}.
      * @throws IllegalArgumentException if {@code charset} is not a {@linkplain StandardCharsets standard charset}.
      */
-    default void setString(long offset, String str, Charset charset) {
+    void setString(long offset, String str, Charset charset);
-        Objects.requireNonNull(charset);
-        Objects.requireNonNull(str);
-        StringSupport.write(this, offset, charset, str);
-    }
 
     /**
      * Creates a memory segment that is backed by the same region of memory that backs the given {@link Buffer} instance.
@@ -1411,10 +1390,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    byte get(ValueLayout.OfByte layout, long offset);
-    default byte get(ValueLayout.OfByte layout, long offset) {
-        return (byte) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes a byte into this segment at the given offset, with the given layout.
@@ -1431,10 +1407,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfByte layout, long offset, byte value);
-    default void set(ValueLayout.OfByte layout, long offset, byte value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads a boolean from this segment at the given offset, with the given layout.
@@ -1450,10 +1423,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    boolean get(ValueLayout.OfBoolean layout, long offset);
-    default boolean get(ValueLayout.OfBoolean layout, long offset) {
-        return (boolean) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes a boolean into this segment at the given offset, with the given layout.
@@ -1470,10 +1440,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfBoolean layout, long offset, boolean value);
-    default void set(ValueLayout.OfBoolean layout, long offset, boolean value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads a char from this segment at the given offset, with the given layout.
@@ -1489,10 +1456,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    char get(ValueLayout.OfChar layout, long offset);
-    default char get(ValueLayout.OfChar layout, long offset) {
-        return (char) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes a char into this segment at the given offset, with the given layout.
@@ -1509,10 +1473,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfChar layout, long offset, char value);
-    default void set(ValueLayout.OfChar layout, long offset, char value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads a short from this segment at the given offset, with the given layout.
@@ -1528,10 +1489,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    short get(ValueLayout.OfShort layout, long offset);
-    default short get(ValueLayout.OfShort layout, long offset) {
-        return (short) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes a short into this segment at the given offset, with the given layout.
@@ -1548,10 +1506,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfShort layout, long offset, short value);
-    default void set(ValueLayout.OfShort layout, long offset, short value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads an int from this segment at the given offset, with the given layout.
@@ -1567,10 +1522,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    int get(ValueLayout.OfInt layout, long offset);
-    default int get(ValueLayout.OfInt layout, long offset) {
-        return (int) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes an int into this segment at the given offset, with the given layout.
@@ -1587,10 +1539,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfInt layout, long offset, int value);
-    default void set(ValueLayout.OfInt layout, long offset, int value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads a float from this segment at the given offset, with the given layout.
@@ -1606,10 +1555,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    float get(ValueLayout.OfFloat layout, long offset);
-    default float get(ValueLayout.OfFloat layout, long offset) {
-        return (float)layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes a float into this segment at the given offset, with the given layout.
@@ -1626,10 +1572,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfFloat layout, long offset, float value);
-    default void set(ValueLayout.OfFloat layout, long offset, float value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads a long from this segment at the given offset, with the given layout.
@@ -1645,10 +1588,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    long get(ValueLayout.OfLong layout, long offset);
-    default long get(ValueLayout.OfLong layout, long offset) {
-        return (long) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes a long into this segment at the given offset, with the given layout.
@@ -1665,10 +1605,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfLong layout, long offset, long value);
-    default void set(ValueLayout.OfLong layout, long offset, long value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads a double from this segment at the given offset, with the given layout.
@@ -1684,10 +1621,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in the provided layout.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    double get(ValueLayout.OfDouble layout, long offset);
-    default double get(ValueLayout.OfDouble layout, long offset) {
-        return (double) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes a double into this segment at the given offset, with the given layout.
@@ -1704,10 +1638,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void set(ValueLayout.OfDouble layout, long offset, double value);
-    default void set(ValueLayout.OfDouble layout, long offset, double value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads an address from this segment at the given offset, with the given layout. The read address is wrapped in
@@ -1729,10 +1660,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraint</a> in {@code T}.
      * @throws IndexOutOfBoundsException if {@code offset > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    MemorySegment get(AddressLayout layout, long offset);
-    default MemorySegment get(AddressLayout layout, long offset) {
-        return (MemorySegment) layout.varHandle().get(this, offset);
-    }
 
     /**
      * Writes an address into this segment at the given offset, with the given layout.
@@ -1750,10 +1678,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      * @throws UnsupportedOperationException if {@code value} is not a {@linkplain #isNative() native} segment.
      */
-    @ForceInline
+    void set(AddressLayout layout, long offset, MemorySegment value);
-    default void set(AddressLayout layout, long offset, MemorySegment value) {
-        layout.varHandle().set(this, offset, value);
-    }
 
     /**
      * Reads a byte from this segment at the given index, scaled by the given layout size.
@@ -1772,12 +1697,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    byte getAtIndex(ValueLayout.OfByte layout, long index);
-    default byte getAtIndex(ValueLayout.OfByte layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (byte) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Reads a boolean from this segment at the given index, scaled by the given layout size.
@@ -1796,12 +1716,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    boolean getAtIndex(ValueLayout.OfBoolean layout, long index);
-    default boolean getAtIndex(ValueLayout.OfBoolean layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (boolean) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Reads a char from this segment at the given index, scaled by the given layout size.
@@ -1820,12 +1735,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    char getAtIndex(ValueLayout.OfChar layout, long index);
-    default char getAtIndex(ValueLayout.OfChar layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (char) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Writes a char into this segment at the given index, scaled by the given layout size.
@@ -1845,12 +1755,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfChar layout, long index, char value);
-    default void setAtIndex(ValueLayout.OfChar layout, long index, char value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Reads a short from this segment at the given index, scaled by the given layout size.
@@ -1869,12 +1774,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    short getAtIndex(ValueLayout.OfShort layout, long index);
-    default short getAtIndex(ValueLayout.OfShort layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (short) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Writes a byte into this segment at the given index, scaled by the given layout size.
@@ -1894,13 +1794,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfByte layout, long index, byte value);
-    default void setAtIndex(ValueLayout.OfByte layout, long index, byte value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-
-    }
 
     /**
      * Writes a boolean into this segment at the given index, scaled by the given layout size.
@@ -1920,12 +1814,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfBoolean layout, long index, boolean value);
-    default void setAtIndex(ValueLayout.OfBoolean layout, long index, boolean value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Writes a short into this segment at the given index, scaled by the given layout size.
@@ -1945,12 +1834,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfShort layout, long index, short value);
-    default void setAtIndex(ValueLayout.OfShort layout, long index, short value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Reads an int from this segment at the given index, scaled by the given layout size.
@@ -1969,12 +1853,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    int getAtIndex(ValueLayout.OfInt layout, long index);
-    default int getAtIndex(ValueLayout.OfInt layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (int) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Writes an int into this segment at the given index, scaled by the given layout size.
@@ -1994,12 +1873,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfInt layout, long index, int value);
-    default void setAtIndex(ValueLayout.OfInt layout, long index, int value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Reads a float from this segment at the given index, scaled by the given layout size.
@@ -2018,12 +1892,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    float getAtIndex(ValueLayout.OfFloat layout, long index);
-    default float getAtIndex(ValueLayout.OfFloat layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (float) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Writes a float into this segment at the given index, scaled by the given layout size.
@@ -2043,12 +1912,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfFloat layout, long index, float value);
-    default void setAtIndex(ValueLayout.OfFloat layout, long index, float value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Reads a long from this segment at the given index, scaled by the given layout size.
@@ -2067,12 +1931,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    long getAtIndex(ValueLayout.OfLong layout, long index);
-    default long getAtIndex(ValueLayout.OfLong layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (long) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Writes a long into this segment at the given index, scaled by the given layout size.
@@ -2092,12 +1951,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfLong layout, long index, long value);
-    default void setAtIndex(ValueLayout.OfLong layout, long index, long value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Reads a double from this segment at the given index, scaled by the given layout size.
@@ -2116,12 +1970,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    double getAtIndex(ValueLayout.OfDouble layout, long index);
-    default double getAtIndex(ValueLayout.OfDouble layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (double) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Writes a double into this segment at the given index, scaled by the given layout size.
@@ -2141,12 +1990,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      */
-    @ForceInline
+    void setAtIndex(ValueLayout.OfDouble layout, long index, double value);
-    default void setAtIndex(ValueLayout.OfDouble layout, long index, double value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Reads an address from this segment at the given at the given index, scaled by the given layout size. The read address is wrapped in
@@ -2171,12 +2015,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws IndexOutOfBoundsException if {@code index * byteSize()} overflows.
      * @throws IndexOutOfBoundsException if {@code index * byteSize() > byteSize() - layout.byteSize()}.
      */
-    @ForceInline
+    MemorySegment getAtIndex(AddressLayout layout, long index);
-    default MemorySegment getAtIndex(AddressLayout layout, long index) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return (MemorySegment) layout.varHandle().get(this, index * layout.byteSize());
-    }
 
     /**
      * Writes an address into this segment at the given index, scaled by the given layout size.
@@ -2197,12 +2036,7 @@ public sealed interface MemorySegment permits AbstractMemorySegmentImpl {
      * @throws UnsupportedOperationException if this segment is {@linkplain #isReadOnly() read-only}.
      * @throws UnsupportedOperationException if {@code value} is not a {@linkplain #isNative() native} segment.
      */
-    @ForceInline
+    void setAtIndex(AddressLayout layout, long index, MemorySegment value);
-    default void setAtIndex(AddressLayout layout, long index, MemorySegment value) {
-        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        layout.varHandle().set(this, index * layout.byteSize(), value);
-    }
 
     /**
      * Compares the specified object with this memory segment for equality. Returns {@code true} if and only if the specified

src/java.base/share/classes/jdk/internal/foreign/AbstractMemorySegmentImpl.java

@@ -36,6 +36,7 @@ import java.nio.FloatBuffer;
 import java.nio.IntBuffer;
 import java.nio.LongBuffer;
 import java.nio.ShortBuffer;
+import java.nio.charset.Charset;
 import java.util.*;
 import java.util.function.BiFunction;
 import java.util.function.Consumer;
@@ -122,6 +123,12 @@ public abstract sealed class AbstractMemorySegmentImpl
         return asSliceNoCheck(offset, newSize);
     }
 
+    @Override
+    public MemorySegment asSlice(long offset, MemoryLayout layout) {
+        Objects.requireNonNull(layout);
+        return asSlice(offset, layout.byteSize(), layout.byteAlignment());
+    }
+
     @Override
     @CallerSensitive
     public final MemorySegment reinterpret(long newSize, Arena arena, Consumer<MemorySegment> cleanup) {
@@ -272,6 +279,18 @@ public abstract sealed class AbstractMemorySegmentImpl
         return Optional.empty();
     }
 
+    @Override
+    public MemorySegment copyFrom(MemorySegment src) {
+        MemorySegment.copy(src, 0, this, 0, src.byteSize());
+        return this;
+    }
+
+    @Override
+    public long mismatch(MemorySegment other) {
+        Objects.requireNonNull(other);
+        return MemorySegment.mismatch(this, 0, byteSize(), other, 0, other.byteSize());
+    }
+
     @Override
     public void load() {
         throw notAMappedSegment();
@@ -732,4 +751,264 @@ public abstract sealed class AbstractMemorySegmentImpl
             throw new IllegalArgumentException("Not a supported array class: " + arrayType.getSimpleName());
         }
     }
+
+    // accessors
+
+    @ForceInline
+    @Override
+    public byte get(ValueLayout.OfByte layout, long offset) {
+        return (byte) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfByte layout, long offset, byte value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public boolean get(ValueLayout.OfBoolean layout, long offset) {
+        return (boolean) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfBoolean layout, long offset, boolean value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public char get(ValueLayout.OfChar layout, long offset) {
+        return (char) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfChar layout, long offset, char value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public short get(ValueLayout.OfShort layout, long offset) {
+        return (short) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfShort layout, long offset, short value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public int get(ValueLayout.OfInt layout, long offset) {
+        return (int) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfInt layout, long offset, int value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public float get(ValueLayout.OfFloat layout, long offset) {
+        return (float) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfFloat layout, long offset, float value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public long get(ValueLayout.OfLong layout, long offset) {
+        return (long) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfLong layout, long offset, long value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public double get(ValueLayout.OfDouble layout, long offset) {
+        return (double) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(ValueLayout.OfDouble layout, long offset, double value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public MemorySegment get(AddressLayout layout, long offset) {
+        return (MemorySegment) layout.varHandle().get(this, offset);
+    }
+
+    @ForceInline
+    @Override
+    public void set(AddressLayout layout, long offset, MemorySegment value) {
+        layout.varHandle().set(this, offset, value);
+    }
+
+    @ForceInline
+    @Override
+    public byte getAtIndex(ValueLayout.OfByte layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (byte) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public boolean getAtIndex(ValueLayout.OfBoolean layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (boolean) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public char getAtIndex(ValueLayout.OfChar layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (char) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfChar layout, long index, char value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public short getAtIndex(ValueLayout.OfShort layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (short) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfByte layout, long index, byte value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfBoolean layout, long index, boolean value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfShort layout, long index, short value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public int getAtIndex(ValueLayout.OfInt layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (int) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfInt layout, long index, int value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public float getAtIndex(ValueLayout.OfFloat layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (float) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfFloat layout, long index, float value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public long getAtIndex(ValueLayout.OfLong layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (long) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfLong layout, long index, long value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public double getAtIndex(ValueLayout.OfDouble layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (double) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(ValueLayout.OfDouble layout, long index, double value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @ForceInline
+    @Override
+    public MemorySegment getAtIndex(AddressLayout layout, long index) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        return (MemorySegment) layout.varHandle().get(this, index * layout.byteSize());
+    }
+
+    @ForceInline
+    @Override
+    public void setAtIndex(AddressLayout layout, long index, MemorySegment value) {
+        Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
+        layout.varHandle().set(this, index * layout.byteSize(), value);
+    }
+
+    @Override
+    public String getString(long offset) {
+        return getString(offset, sun.nio.cs.UTF_8.INSTANCE);
+    }
+
+    @Override
+    public String getString(long offset, Charset charset) {
+        Objects.requireNonNull(charset);
+        return StringSupport.read(this, offset, charset);
+    }
+
+    @Override
+    public void setString(long offset, String str) {
+        Objects.requireNonNull(str);
+        setString(offset, str, sun.nio.cs.UTF_8.INSTANCE);
+    }
+
+    @Override
+    public void setString(long offset, String str, Charset charset) {
+        Objects.requireNonNull(charset);
+        Objects.requireNonNull(str);
+        StringSupport.write(this, offset, charset, str);
+    }
 }

src/java.base/share/classes/jdk/internal/foreign/layout/AbstractLayout.java

@@ -25,16 +25,26 @@
  */
 package jdk.internal.foreign.layout;
 
+import jdk.internal.foreign.LayoutPath;
+import jdk.internal.foreign.LayoutPath.PathElementImpl.PathKind;
 import jdk.internal.foreign.Utils;
 
 import java.lang.foreign.GroupLayout;
 import java.lang.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout.PathElement;
 import java.lang.foreign.SequenceLayout;
 import java.lang.foreign.StructLayout;
 import java.lang.foreign.UnionLayout;
 import java.lang.foreign.ValueLayout;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.invoke.VarHandle;
+import java.util.EnumSet;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
+import java.util.function.Function;
 
 public abstract sealed class AbstractLayout<L extends AbstractLayout<L> & MemoryLayout>
         permits AbstractGroupLayout, PaddingLayoutImpl, SequenceLayoutImpl, ValueLayouts.AbstractValueLayout {
@@ -140,4 +150,72 @@ public abstract sealed class AbstractLayout<L extends AbstractLayout<L> & Memory
         return value;
     }
 
+    public long scale(long offset, long index) {
+        if (offset < 0) {
+            throw new IllegalArgumentException("Negative offset: " + offset);
+        }
+        if (index < 0) {
+            throw new IllegalArgumentException("Negative index: " + index);
+        }
+
+        return Math.addExact(offset, Math.multiplyExact(byteSize(), index));
+    }
+
+    public MethodHandle scaleHandle() {
+        class Holder {
+            static final MethodHandle MH_SCALE;
+            static {
+                try {
+                    MH_SCALE = MethodHandles.lookup().findVirtual(MemoryLayout.class, "scale",
+                            MethodType.methodType(long.class, long.class, long.class));
+                } catch (ReflectiveOperationException e) {
+                    throw new ExceptionInInitializerError(e);
+                }
+            }
+        }
+        return Holder.MH_SCALE.bindTo(this);
+    }
+
+
+    public long byteOffset(PathElement... elements) {
+        return computePathOp(LayoutPath.rootPath((MemoryLayout) this), LayoutPath::offset,
+                EnumSet.of(PathKind.SEQUENCE_ELEMENT, PathKind.SEQUENCE_RANGE, PathKind.DEREF_ELEMENT), elements);
+    }
+
+    public MethodHandle byteOffsetHandle(PathElement... elements) {
+        return computePathOp(LayoutPath.rootPath((MemoryLayout) this), LayoutPath::offsetHandle,
+                EnumSet.of(PathKind.DEREF_ELEMENT), elements);
+    }
+
+    public VarHandle varHandle(PathElement... elements) {
+        Objects.requireNonNull(elements);
+        if (this instanceof ValueLayout vl && elements.length == 0) {
+            return vl.varHandle(); // fast path
+        }
+        return computePathOp(LayoutPath.rootPath((MemoryLayout) this), LayoutPath::dereferenceHandle,
+                Set.of(), elements);
+    }
+
+    public MethodHandle sliceHandle(PathElement... elements) {
+        return computePathOp(LayoutPath.rootPath((MemoryLayout) this), LayoutPath::sliceHandle,
+                Set.of(PathKind.DEREF_ELEMENT), elements);
+    }
+
+    public MemoryLayout select(PathElement... elements) {
+        return computePathOp(LayoutPath.rootPath((MemoryLayout) this), LayoutPath::layout,
+                EnumSet.of(PathKind.SEQUENCE_ELEMENT_INDEX, PathKind.SEQUENCE_RANGE, PathKind.DEREF_ELEMENT), elements);
+    }
+
+    private static <Z> Z computePathOp(LayoutPath path, Function<LayoutPath, Z> finalizer,
+                                       Set<PathKind> badKinds, PathElement... elements) {
+        Objects.requireNonNull(elements);
+        for (PathElement e : elements) {
+            LayoutPath.PathElementImpl pathElem = (LayoutPath.PathElementImpl)Objects.requireNonNull(e);
+            if (badKinds.contains(pathElem.kind())) {
+                throw new IllegalArgumentException(String.format("Invalid %s selection in layout path", pathElem.kind().description()));
+            }
+            path = pathElem.apply(path);
+        }
+        return finalizer.apply(path);
+    }
 }